In constructing furniture or similar items, woodworkers and craftsman expend substantial effort in fabricating joints (e.g., dovetail and box joints) that are not only precise and sturdy, but also are aesthetically pleasing. For example, the use of dovetail joints to fit parts of furniture together is an admirable and old woodworker art which is generally pleasing to the eye, particularly when the joints are created by hand with a nonuniform, classic appearance. Dovetails made with perfectly fitting joints are considered to be the product of highly skilled craftsmen. Those steeped in knowledge of the art carefully review the quality of the joints and grade the craftsman's woodworking abilities.
A dovetail joint has two different parts, or components, called tails and pins, which fit together in a complimentary fashion to form the attractive looking, strong joint. The most popular dovetail joints are the "half-blind" and the "through" dovetail joints. The half-blind joint can only be seen on one side of the two joined surfaces and is primarily used for flushed and lipped drawers. The through joint can be seen on both surfaces. Whether half-blind or through dovetail joints are being crafted, it is almost axiomatic that the more tails and pins required for a particular woodworking project, the more time-consuming the fabrication becomes. For those who make a living constructing furniture that typically incorporates dovetail joints, a compromise has to be struck between the number of pins seen in the joint and the expense of forming the joint. Also, when too few pins are used in joining a pair of wood members, the resulting joint may be structurally too weak. To reduce the amount of time required to produce dovetail joints, many craftsmen resort to using various types of commercially available "jigs." A "jig," for purposes of this description, may be defined as a device used to mechanically maintain the correct positional relationship between a working piece and the tool. A multi-functional jig producing half-blind or through joints of variable spacing is available from Leigh Industries in Port Coquitlam, British Columbia, Canada. Similarly, Porter-Cable produces a jig, known as the "Omnijig," which is capable of producing various types of dovetail joints, including half-blind and through joints. The jigs, while providing admirable dovetail joints, are complicated to set up and use, and provide only joints of limited length.
Perhaps the easiest-to-use jig for the making of through dovetail joints is the Keller dovetail "template" system, available from Keller & Co., of Petaluma, Calif., which involves, in part, the use of a template. In the woodworking art, the terms "jig" and "template" are used interchangeably. However, to promote clarity in this description, a "template" is distinguished from the aforementioned definition of a "jig" by being defined as a gauge, pattern or mold, typically formed in a thin plate or board, used as a guide for a tool, such as a router, to replicate the pattern of the template in a piece of material secured or fixed to the template. Similarly, a "pattern plate," again for purposes of this description, is defined as a plate having a pattern serving as a guide for a router and the like to fabricate a configuration in a working piece. The Keller system uses machined pattern plates as a guide for a router bit to directly fabricate the mating parts of a dovetail joint, namely, the pins and tails. The Keller system, described in detail in several patents, including U.S. Pat. Nos. 4,168,730; 5,139,062; and 5,199,477, is easy to use and can provide variable length dovetail joints with variable spacing. The Keller system, however, is cumbersome when used to make dovetail joints with variable spacing and often requires the purchase of a different jig. Moreover, the individual cutters and pattern plates comprising the system are expensive and must be replaced when accidentally damaged by a router bit during use or bent by accidentally dropping the plates. The home craftsman has limited ability to repurchase such pattern plates.
U.S. Pat. No. 5,692,861, issued to Stottmann, overcomes many of the problems encountered in the prior art. The Stottmann device is a single planar member having a pair of sides in which the member defines first and second pluralities of elongated openings. The first plurality of elongated openings is positioned adjacent one of the sides of the member, each of said elongated openings extending between oppositely disposed first and second circular ends. These openings further have opposing parallel sides spaced a predetermined distance apart. The first circular ends have diameters substantially equal to this distance, while the second circular ends have diameters larger than this distance.
The second plurality of openings in the Stottmann template is positioned adjacent the other side of the planar member. A first portion of the second openings has spaced opposing sides that are parallel, while a second portion of the second openings has opposing sides that converge toward one another and away from the first portion. The convergence of the sides of the second openings defines an angle substantially equal to the slope angle of the preselected dovetail cutter bit.
In using this template, the template is preferably first positioned over a rectangular form, comprised of inexpensive, but cuttable material. In one preferred method of construction, starter holes are also drilled into the underlying form. A starter bit is passed through the enlarged diameter holes of selected openings of the plurality of first openings, and then through selected openings of the second portion of the plurality of second openings. A pattern cutter bit, of a diameter less than the diameter of the starter holes, with a rotatable guide bearing is inserted through the openings so that the cutter bit extends into the starter holes, and the rotatable bearing is rotatably engaged with the side of the openings. A plurality of pin openings and a plurality of dovetail openings are then cut in the form. The form, now a unitary pattern plate, is removed from the template and ready to use.
The described Stottmann device thus provides for the creation of a fixed-length pattern plate which is then used for fabricating the dovetails and pins. This is preferred because the template itself is subject to damage if it is used to directly cut the dovetails and pins, and replacement of the template can be costly.
U.S. Pat. No. 6,012,497, also issued to Stottmann, further improves upon the device of the '861 patent and describes an inexpensive device that allows for the creation of dovetail joints of unlimited length. Furthermore, this device can be used both as a pattern plate, eliminating the intermediate step of using a template to cut a pattern plate, or as a template.
Specifically, the device described in the '497 patent is a panel that can used either as a pattern plate or a template. This panel is preferably a planar member having a generally rectangular shape, including a pair of sides, a left edge, and a right edge. The panel defines first and second pluralities of elongated openings. The first plurality of elongated openings is positioned adjacent one of the sides of the panel, each of the openings extending between oppositely disposed first and second circular ends. Each opening further has opposing parallel sides spaced a predetermined distance apart. The first circular end has a diameter substantially equal to this distance, while the second circular end has a diameter greater than this distance. Additionally, the panel defines "half-openings" along its left and right edges. Thus, when two panels are placed side-by-side, the adjacent half-openings form the above described first elongated opening.
The second plurality of openings is positioned adjacent the other side of the panel. A first portion of the second openings has spaced opposing sides that are parallel, while a second portion has opposing sides that converge toward one another. The convergence of the sides of the second openings defines an angle substantially equal to the angle of the preselected dovetail cutter bit. Again, the panel defines "half-openings" along its left and right edges. Thus, when two panels are placed side-by-side, the adjacent half-openings form the above-described second elongated opening.
With the half-openings along either edge of the panel, a series of panels may be placed side-by-side to fabricate dovetails of an unlimited length. Because of the modularity of these panels, if an individual panel is damaged, it may be replaced without affecting the adjacent panels.
Keller, Stottmann, and similar prior art references thus each disclose methods and devices for fabricating dovetail joints wherein the router is passed over and through a template or jig to fabricate the desired joints. Such manipulation of the router, however, may be difficult due to the weight of the router. Furthermore, this manipulation of the router often causes vibrations that can hinder accurate and precise cutting of the pins and tails for dovetail joints.
It is therefore a paramount object of the present invention to provide a jig that secures the working piece and allows the working piece to be passed over a fixed router without sacrificing any of the ease of use or quality associated with the jigs and templates taught by Stottmann and others in the prior art.
It is another important object of the present invention to provide a jig that permits both the jig and the working piece to be passed over a table-mounted router, thereby permitting smaller or thinner pieces of wood to be cut.
It is yet another important object of the present invention to provide for a dovetail jig and router system that minimizes vibrations during the cutting process.
It is still yet another important object of the present invention to provide a jig that can be used with a hand-held router if desired.
These and other objects and advantages of the present invention will become apparent upon a reading of the following description.